Integrated circuit devices often include a plurality of semiconductor devices on a single semiconductor substrate or die. It often is desirable to provide electrical isolation between the various semiconductor devices that are present on the semiconductor substrate, and dielectric-lined trenches have been employed to provide this electrical isolation. As the operating voltage or density (i.e., devices per unit area) on semiconductor substrates is increased, it becomes more difficult to maintain a desired level of electrical isolation among the semiconductor devices. In addition, as the density of devices increases, the achieved level of electrical isolation often varies across the semiconductor substrate or across the die. For example, electrical communication (or punch-through currents) between adjacent semiconductor devices often is more difficult to regulate or block. As another example, parasitic field effect transistor (FET) currents between individual semiconductor devices and the semiconductor substrate often are more difficult to regulate or block.